diff --git a/GNUmakefile.in b/GNUmakefile.in
index 1732cff..7d4d21c 100644
--- a/GNUmakefile.in
+++ b/GNUmakefile.in
@@ -95674,6 +95674,7 @@ $(GENSOURCES_WEBCORE)/XPathGrammar.h: $(GENSOURCES_WEBCORE)/XPathGrammar.cpp
 $(GENSOURCES_WEBCORE)/XPathGrammar.cpp: $(WebCore)/xml/XPathGrammar.y
 	$(AM_V_GEN)
 	$(AM_V_at)perl $(WebCore)/css/makegrammar.pl --outputDir $(GENSOURCES_WEBCORE) --bison "$(BISON)" --symbolsPrefix xpathyy $<
+	$(AM_V_at)cp $(GENSOURCES_WEBCORE)/XPathGrammar.h $(GENSOURCES_WEBCORE)/XPathGrammar.hpp
 
 # MathML tag and attribute names, and element factory
 DerivedSources/WebCore/MathMLElementFactory.h: DerivedSources/WebCore/MathMLElementFactory.cpp
@@ -95732,6 +95733,7 @@ DerivedSources/WebCore/CSSGrammar.h: $(GENSOURCES_WEBCORE)/CSSGrammar.cpp
 DerivedSources/WebCore/CSSGrammar.cpp: $(WebCore)/css/CSSGrammar.y.in
 	$(AM_V_GEN)
 	$(AM_V_at)perl -I $(WebCore)/bindings/scripts $(WebCore)/css/makegrammar.pl --extraDefines "$(feature_defines)" --outputDir $(GENSOURCES_WEBCORE) --bison "$(BISON)" --symbolsPrefix cssyy $<
+	$(AM_V_at)cp $(GENSOURCES_WEBCORE)/CSSGrammar.h $(GENSOURCES_WEBCORE)/CSSGrammar.hpp
 
 DerivedSources/WebCore/UserAgentStyleSheetsData.cpp: DerivedSources/WebCore/UserAgentStyleSheets.h
 DerivedSources/WebCore/UserAgentStyleSheets.h: $(WebCore)/css/make-css-file-arrays.pl $(WebCore)/bindings/scripts/preprocessor.pm $(USER_AGENT_STYLE_SHEETS)
